"It has survived changes in the past, and some of those changes are perhaps ones we haven't noticed like the coming of colour and the coming of photography in newspapers, because photographs now are rude about the people who are photographed.

The politicians are caught off guard, they're caught in the sorts of poses that previously only cartoonists could get away with".

– Dr Nick Hiley, British Cartoon Archive

So how do politicians view them? As Secretary for Health, the South Cambridgeshire MP Andrew Lansley was featured from time to time.

He says they're something he and others in politics pay attention to, and enjoy.